https://github.com/dominictarr/map-stream

https://github.com/dominictarr/map-stream

Last synced: about 1 month ago
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• Host: GitHub
• URL: https://github.com/dominictarr/map-stream
• Owner: dominictarr
• License: mit
• Archived: true
• Created: 2012-08-18T12:37:15.000Z (over 12 years ago)
• Default Branch: master
• Last Pushed: 2019-04-01T22:10:00.000Z (over 5 years ago)
• Last Synced: 2024-05-17T17:02:42.775Z (7 months ago)
• Language: JavaScript
• Size: 91.8 KB
• Stars: 121
• Watchers: 7
• Forks: 22
• Open Issues: 12
• Metadata Files:
  • Readme: readme.markdown

Awesome Lists containing this project

• awesome-nodejs - dmap-stream - refactored out of event-stream. (Repository / Streams)
• awesome-nodejs-streams - dominictarr/map-stream - refactored out of event-stream (Modules)

README

        
# MapStream

Refactored out of [event-stream](https://github.com/dominictarr/event-stream)

##map (asyncFunction[, options])

Create a through stream from an asyncronous function.  

``` js

var map = require('map-stream')

map(function (data, callback) {

  //transform data

  // ...

  callback(null, data)

})

```

Each map MUST call the callback. It may callback with data, with an error or with no arguments, 

  * `callback()` drop this data.  

    this makes the map work like `filter`,  

    note:`callback(null,null)` is not the same, and will emit `null`

  * `callback(null, newData)` turn data into newData

    

  * `callback(error)` emit an error for this item.

>Note: if a callback is not called, `map` will think that it is still being processed,   

>every call must be answered or the stream will not know when to end.  

>

>Also, if the callback is called more than once, every call but the first will be ignored.

##Options 

 * `failures` - `boolean` continue mapping even if error occured. On error `map-stream` will emit `failure` event. (default: `false`)